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From: ben@catnip.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: RLL controler
Message-ID: <467@catnip.UUCP>
Date: Thu, 5-Feb-87 21:48:07 EST
Article-I.D.: catnip.467
Posted: Thu Feb  5 21:48:07 1987
Date-Received: Sat, 7-Feb-87 18:27:14 EST
References: <1083@ethos.UUCP> <4791@watmath.UUCP>
Reply-To: ben@catnip.UUCP (Bennett Broder)
Distribution: na
Organization: The Broder Residence, Holmdel, NJ  07733
Lines: 46

In article <4791@watmath.UUCP> rwwetmore@watmath.UUCP (Ross Wetmore [ICR]) writes:
>From article <1083@ethos.UUCP>:
>
>> I just read about the RLL (Run Length Limited) controlers in the
>> Febuary issue of Computer Shoper.  It seems almost too good to be
>> true.  Has anyone tried these controlers that could report on their
>> performance/compatibility?
>
>  I have known of them for some time, but never seemed to get any detailed
>information on them. Since there seem to be a number of users on the net
>with them, perhaps this is a good time and place to ask the following:
>
>1)  What (if any) specific hardware upgrades are required to use RLL
>    controllers besides the controller itself and compatible disk? Are
>    there any modifications to the disk to enable it to run with an RLL
>    (as opposed to normal) controller?

There are no specific hardware upgrades required.  All you need is a PC
or XT clone and a compatible drive.  Generally, most drives with plated
media will work.  I believe Adaptec has also published a list.

>2)  Corollary: how does a standard ROM expecting 17 sectors/track manage
>    to deal with the RLL sectoring?

Simple.  The only ROM on a PC or XT that knows about how many sectors
there are per track is the one on the controller card.  Since the
RLL controller comes with the proper ROM installed this is not a problem.

Note that the reason you haven't seen RLL controllers for the AT and
AT clones is that these machines has 17 sector specific code in ROMs
on the motherboard.

>4)  What OS do you use? Has anyone used RLL disks with MicroPort Unix?
>    Xenix? Are there any problems with interaction or incompatibility
>    with the OS itself, or distributed programs?

Microport Unix runs only on the AT, hence it is incompatible with the
current crop of RLL cards.  I don't know about Xenix, but I can tell
you that it isn't in the list of compatible controller in the release
notes.

-- 

Ben Broder
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